采用密度泛函理论(DFT)考察了丙烷在Pt(111)表面上脱氢生成丙烯的反应机理.通过在Pt(111)面上预吸附一定数量H原子模拟共吸附H对丙烷脱氢过程的影响.结果表明:H共吸附能降低丙烷及其脱氢产物的吸附能,促进丙烯脱附,有利于提高丙烯的选择性;H共吸附会导致丙烷脱氢能垒变大,降低催化剂的脱氢活性;共吸附的影响随着H覆盖率增加而增大.%The Density Functional Theory(DFT) calculations was conducted to investigate the reaction mechanism of propane dehydrogenation on Pt(111). Certain amount of H atoms were pre-adsorbed on the Pt(111) surface to model the co-adsorption effect on propane dehydrogenation process. The results showed that the H co-adsorption could reduce adsorption energies of propane and dehydrogenation product, which indicated a lower barrier for propylene desorption resulting in higher propylene selectivity. The energy barrier for propane dehydrogenation increased due to H co-adsorption, which reduced the catalyst activity on the dehydrogenation process. The co-adsorption impact increased with the increase of H coverage.
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